Sulfurized oil-soluble esters of chlorendic acid



United States Patent SULFURIZED OIL-SOLUBLE ESTERS OF CHLORENDIC ACID No Drawing. Original application Aug. 3, 1956, Ser. No. 602,062. Divided and this application Jan. 12, 1960, Ser. No. 9,145

3 Claims. (Cl. 260-125) This invention relates to sulfurized esters of chlorendic acid, and particularly to the use of such esters in mineral oils to provide extreme pressure lubricants and metalworking oils having improved properties. This invention also relates to extreme pressure lubricants of improved load carrying ability which satisfy the requirements demanded in the lubrication of bearings, gears, and ;he like, subjected to heavy loads per unit area of surace.

' The present invention is particularly concerned with cutting oils used in broaching, gear cutting, hobbing, planing and similar operations in which metal is re- Patented May 23, 1961 ice OR (31- Cl in which R is an unsaturated aliphatic, including cyc1o-- aliphatic, or aromatic hydrocarbon group containing 3 to carbon atoms and R" is hydrogen or the identical or non-identical member selected from the same groupras R. More specifically the unsaturated members include alkenyl, aryl and aral'kenyl groupshsuch as allyl, oleyl, cyclohexenyl, phenyl, and naphthyl ester groups from unsaturated alcohols derived from acidsv such as phenyl acrylic, linoleic, myristoleic, cinnamic, angelic and the moved from the work piece at a comparatively low rate,

e.g. at cutting speeds of 10 to 20 surface feet per minute The metal chips removed vary in thickness from 0.005..

to 0.0005 inch. A major objective of cutting operations of this type is the achievement of a good surface finish, and, therefore, one of the functions of a cutting oil usedin such operations is to improve the surface finish obtained.

Certain short chain chlorinated compounds such as carbon tetrachloride, ethylene dichloride and diisobutylene dichloride are known to be especially effective as additives for broaching and gear cutting oils. Although an excellent surface finish can be obtained on work pieces by the inclusion of carbon tetrachloride in broaching and gear cutting oils, this compound is not suitable as a cutting oil additive for two reasons. First, due to itstvolatili ty, carbon tetrachloride is rapidly lost by evaporation from the cutting oil during use thus necessitating close control of the concentration and frequent replenishment with fresh carbon tetrachloride. Second, carbon tetrachloride is atoxic substance which causes severe'physiological damage when, inhaled as a vapor or when. ah-

sorbed through the skin by contact. Ethylene dichloride is also highly volatile. Diisobutylene dichloride, which might be used as a substitute for carbon tetrachloride due to its lack of toxicity, is objectionable becauseofits highly unpleasant odor which could not be tolerated for the length of'an average working day; Therefore, a need exists for a non-toxic, non-volatile, substantially odorless, mineral oil-soluble additive which imparts extreme pressure properties to a cuttingoil composition.

In accordance with the present invention I have discovered that the addition of oil-soluble sulfurized unsaturated esters of chlorendic acid to mineral lubricating 7 I anhydride.

like, which unsaturated members can, if desired, be sub: stituted as with chlorine for instance. The preferred esters of chlorendic acid are diesters and particularly those in which the ester groups, are mono-olefinic. and contain from 16 to 18 carbon atoms. A preferred diester; can be obtained from the unsaturated alcohols. derived from sperm oil. The esters can be prepared by any, suitable method as, for example, by reacting. chlorendic anhydride with an excess of the appropriate unsaturated alcohol. The reaction can be carried out in the presence of an esterification catalyst such as p-toluene sul'fonie acid' until the theoretical amount of water has been re moved. If desired, the same method of preparation is applicable when using chlorendic acid instead of the In this method two moles of water are evolved for each mole of chlo'rendic diester formed and the waterof reaction maybe removed azeotropically by distillation with a solvent such as benzene or toluene.

In carrying out the sulfurization of the chl'or endic acid ester about one-half to four gram-atoms of elemental sulfur are reacted with each mole of chlorend'ate ester at a temperature of from about 300" to 450 F; Pref erably, however, the'sulfurization is accomplished by-reacting each mole of ester with about one-half to. two gram-atoms ofsulfur at a temperature ofabout 320;. to 375 F. At temperatures below 320 F.'the sulfurization reaction is slow, whereas at higher temperatures, i.e. above 375 F., large. amounts ofisulfur are lost in the form of hydrogen sulfide,

' signed.

oils affords extreme pressure lubricating compositions of improved load carrying ability under conditions of high mechanical loading. As metal working fluids the .l'ubri eating compositions of this invention are advantageous inasmuch as they are capable of reducing the surface N roughness of machined parts. v

The oil-soluble sulfurized esters added to mineral lub ricating oils in preparing the compositions of this invention can be obtained by sulfurizing an oil-soluble chlorendic acid ester of the following formula:

lubricants.

The amount of the sulfurized esters of chlor endic acid added to the mineral oil for the preparationyof the-compositions is suflicient to impart increased load carrying capacity to the base oil and may vary, dependingupon the'serviceqapplication for which the composition is-,dea In general, for metal working fluids usedas cutting oils, and depending upon the smoothness of the work piece desired,,the, amount of, snlfurized ester re quired to be added, will depend uponthe particularz'es'ter and will usually vary between about 5 to, 35% by weight of the oil base. The compounding of oils for useas ex treme pressure lubricant-s, as distinguished from cutting oils, requires about0.5 to-10% by weighhof-the sulfurized ester material. a The following examples, which are not to be considered limiting', i llustrate the preparation of sulfurized'chlorendic acid esters and the compounding of; mineral -lubrica'ting oils containing the same for useas extreme pressure' Preparation of oleyl eh lorendate diest ei" A mixture of 705 grams of chlorendic anhydride and 1000 grams of commercial oleyl alcohol (hydroxyl number 214, iodine number 83) was dissolved in 1000 cc. of

3, xylene and grams of p-toluene sulfonic acid were added as a catalyst. The mixture was heated to reflux for 10 hours until 44 cc. of water had been collected in a Dean-Stark trap attached to the esterification apparatus. The reaction mixture was then washed Once with 0.25 N KOH in 1:1 alcohol-water and twice with 1:1 alcoholwater. After clarification by filtration, the reaction mixture was freed of xylene by distillation and the last traces of solvent were removed under vacuum at a pot temperature of 300 F. The reaction product was a dark, oily liquid with the characteristics listed below:

Percent chlorine 24.0 Acid number 0.28 Saponification number 127.9 Iodine number 50.1

EXAMPLE II Preparation of allyl chlorendate diester p-toluene sulfonic acid as a catalyst was refluxed for 32 1 hours and the excess allyl alcohol was removed by distillation. The residue was taken up in a mixture of pentane andv benzene and was washed first with aqueous KOH and then with water. The solvent was distilled 01f, first at atmospheric pressure and finally at 2-3 mm. pressure. The product was a dark, viscous liquid having the following characteristics:

Percent chlorine 44.8 Acid number 0.10 Saponification number 236.8 Iodine number 107.1

EXAMPLE III Sulfurz'zation of oleyl chlorendate diester EXAMPLE IV V Sulfurization of allyl chlorendate diester A mixture of 512 grams of diallyl chlorendate and 60 grams of sulfur was heated in the temperature range 3002-3607 'F. for 6 hours. When the reaction mixture cooled to roomtemperature it solidified to a black, brittle material which melted to' a fluid at 280 320 F; The product contained 11.1% sulfur and 40.5% chlorine. It

was not a homogeneous substance sinceit was only partly soluble in an acid-refined Coastal oil. The insoluble residue was a tar.

EXAMPLE v compounded oils containing sulfurized oleyl chlorendate diester Compounded oils were prepared with sulfurized dioleyl chlorendate by blending the additive into acid refined Coastal naphthenic oils at 150 to 210 F. The additive remained completely dissolved in the oil at room tem perature. The following blends were made up in mineral oils of difierent viscosities.

Mineral oil compositions of this invention are also prepared by adding at 175 F. 5, 10 and 25 percent of the sulfurized diester of Example IV to a Coastal naphthenic oil of 150 SUS at 100 F. viscosity.

The advantages obtained by employing the lubricating compositions of the present invention as cutting oils became particularly apparent in cases where the surface finish requirements for the work piece are unusually stringent. The effect of oil blends containing sulfurized dioleyl chlorendate as a cutting oil was demonstrated by means of an orthogonally cutting planer operation. As shown below various oil blends prepared in accordance with Example V were rated according to the surface roughness of the cut surface as determined by a profilometric measuring instrument. Results are shown in Table I below.

TAB LE I Surface Roughness, microlnches on Blend of Ex. 5

A181 1045 A181 4150 AMS 6260 A181 8620 Steel Steel Steel Steel 1 76 56 50 56 2 95 80 7 3 Base Oil 173 98 131 85 Oil blends 3 and 4 of Example 5 which contained 10% and 5% by weight of sulfurized dioleyl chlorendate, respectively, were tested for extreme pressure load carrying ability in the Falex lubricant testing apparatus. A similar oil blend containing 26% of the unsulfurized diester was also tested. In this test an uncompounded mineral oil does not permit the test to run for the three minute break-in period at 300 pounds without failure. As shown below, oil blends containing sulfurized oleyl chlorendate diester provide extreme pressure lubricants of improved load carrying ability.

Additive, Failure Oil Blend of Example 5 Wt. Per- Load, lbs.

cent 7 10 2, 750 4 5 2, 750 5 (contained unsulfurized diester) 26 l, 250

The present application is a division of Serial No. 602,062, filed August 3, 1956, now Patent No. 2,969,326.

I claim:

1. A sulfurized oil-soluble ester of chlorendic acid produced by reacting sulfur and an oil-soluble chlorendic acid ester in a ratio of about one-half to four gram-atoms of sulfur to one'mole of chlorendic acid esterin which saidester group is anunsaturated hydrocarbon radical containing from 3 to 20 carbon atoms. V

2. The product of c laim l wherein the ester of chlorendic acid is a diester in which each ester group is an aliphatic unsaturated hydrocarbon radical containing from 3 to 20 carbon atoms.

. 3. 'The product of claim 2 wherein the chlorendic acid diester is dioleyl chlorendate.

No references cited. 

1. A SULFURIZED OIL-SOLUBLE ESTER OF CHLORENDIC ACID PRODUCED BY REACTING SULFUR AND AN OIL-SOLUBLE CHLORENDIC ACID ESTER IN A RATIO OF ABOUT ONE-HALF TO FOUR GRAM-ATOMS OF SULFUR TO ONE MOLE OF CHLORENDIC ACID ESTER IN WHICH SAID ESTER GROUP IS AN UNSATURATED HYDROCARBON RADICAL CONTAINING FROM 3 TO 20 CARBON ATOMS. 